An alignment film is given a 2-layer structure comprising a photoalignment film that is photoalignable and a low-resistivity alignment film whose resistivity is smaller than that of the photoalignment film. The photoalignment film is formed by a polyimide whose precursor is polyamide acid alkyl ester, the number molecular weight of the photoalignment film is large, and the stability of alignment of the photoalignment film by photoalignment is excellent. The low-resistivity alignment film is formed by a polyimide whose precursor is polyamide acid, the number molecular weight of the low-resistivity alignment film is small, and the resistivity of the low-resistivity alignment film is small. The 2-layer structure alignment film can be maintaining an excellent photoalignment characteristic, so DC afterimages can be controlled.

A liquid crystal display capable of reducing the occurrence of defective display due to variations in the initial alignment direction of a liquid crystal alignment control film in a liquid crystal display of an IPS scheme, realizing the stable liquid crystal alignment, providing excellent mass productivity, and having high image quality with a higher contrast ratio. The liquid crystal display has a liquid crystal layer disposed between a pair of substrates, at least one of the substrates being transparent, and an alignment control film formed between the liquid crystal layer and the substrate. At least one of the alignment control films 109 comprises photoreactive polyimide and/or polyamic acid provided with an alignment control ability by irradiation of substantially linearly polarized light.

According to one embodiment, a display device includes first and second substrates and a liquid crystal layer. The first substrate includes pixel electrodes and a first alignment film. The second substrate includes a common electrode and a second alignment film. The liquid crystal layer is provided between the alignment films and contains a streaky polymer and liquid crystal molecules. The first alignment film includes flat areas. A first director of the liquid crystal molecules located near the flat areas is substantially parallel to a horizontal plane in a state where no potential difference is formed between the pixel electrodes and the common electrode.

An IPS type liquid crystal display device superior in mass productivity and improved in image quality with a higher contrast ratio by decreasing the occurrence of defective display due to the disorder of the initial liquid crystal alignment by the liquid orientation control film and realizing stable alignment of liquid crystals comprises: a pair of substrates, at least one which is transparent; a liquid crystal layer disposed between the pair of substrates; a group of electrodes formed on at least one of the pair of substrates to apply an electric field to the liquid crystal layer; plural active elements connected to the group of electrodes; and an orientation control film disposed on at least one of the pair of substrates, wherein said orientation control film is made of a photosensitive polyimide and a polyamide acid ester and is given orientation control ability by being irradiated with substantially linearly polarized light.

To provide an optical film having excellent visibility in a wide angle direction. An optical film including at least one resin selected from the group consisting of a polyimide-based resin and a polyamide-based resin and having a total light transmittance of 85% or more and a haze of 0.5% or less, wherein when a direction parallel to a machine direction in a plane of the optical film during production of the optical film is defined as an MD direction and a direction vertical to the machine direction is defined as a TD direction, a first transmission image clarity value C.sub.60(MD) in a direction inclined 60 in the MD direction from a vertical direction to the plane of the optical film, a second transmission image clarity value C.sub.60(TD) in a direction inclined 60 in the TD direction from the vertical direction, and a third transmission image clarity value C.sub.0 of the vertical direction which are obtained when a width of an optical comb is 0.125 mm in accordance with JIS K 7374 satisfy Formulae,

Formula (1):

87%C.sub.60(MD)100%(1),

Formula (2):

87%C.sub.60(TD)100%(2), and

Formula (3):

0.8C.sub.60(MD)/C.sub.01.0(3).

A composition contains a first polyamic acid and a second polyamic acid. The first polyamic acid has at least one of a photoreactive functional group and a vertical alignment group. The second polyamic acid has a repeat unit that has a pendant alkoxysilyl group.

A liquid crystal aligning agent composition for preparing a liquid crystal alignment film having enhanced stability and exhibiting excellent electrical characteristics, a method for preparing a liquid crystal alignment film using the same, and a liquid crystal alignment film and a liquid crystal display device using the liquid crystal alignment film.

A liquid crystal aligning agent which contains a polymer (A) and a polymer (B). Polymer (A): A polymer which has at least one structural unit U1 selected from the group consisting of structural units represented by formula (1) and structural units represented by formula (2), and a structural unit U2 derived from at least one monomer selected from the group consisting of styrene monomers and (meth)acrylic monomers. Polymer (B): At least one polymer selected from the group consisting of polyamic acids, polyamic acid esters and polyimides. In the formulae, R.sup.7 represents a monovalent organic group having one or more carbon atoms; R.sup.8 represents a monovalent organic group having one or more carbon atoms; and R.sup.9 represents a hydrogen atom or a monovalent organic group having one or more carbon atoms.

The present invention provides a liquid crystal display device includes: a pair of substrates; a liquid crystal layer held between the substrates; an alignment film disposed on a liquid crystal layer side surface of at least one of the substrates; and a polymer layer disposed between the liquid crystal layer and the alignment film, the liquid crystal layer containing liquid crystal compounds aligned in a predetermined direction with no voltage applied, the alignment film containing a first polymer containing in its main chain at least one selected from a polyamic acid structure and a polyimide structure, the polymer layer containing a second polymer obtained by polymerizing at least one monomer containing an azobenzene group, the second polymer covalently bonded to the first polymer.

A liquid crystal display device (100) includes a pair of substrates (11, 21), a liquid crystal layer (30) sandwiched between the pair of substrates (11, 21), an alignment film (12) disposed between the liquid crystal layer (30) and at least one substrate (11), and an alignment-sustaining layer (40) disposed between the alignment film (12) and the liquid crystal layer (30) and regulating the tilt direction of at least liquid crystal molecules close to the alignment film (12) among the liquid crystal molecules constituting the liquid crystal layer (30). The alignment film (12) contains a polymer compound having a functional group represented by the following Formula (1):

##STR00001##